Measurement of radon in air using a radon-²¹⁸Po calibration curve determined by an absorptive non-volatile liquid scintillator

This work reports a novel method for determining ²²²Rn (radon) in air using a radon-²¹⁸Po calibration curve constructed by an absorbable non-volatile liquid scintillator (NVLS). The ability of this method to detect low natural concentrations of radon was confirmed from linear extrapolation of the curve between 500 and 8000 Bq/m³. The calibration curve was created from data obtained from measurements performed in a radon calibration chamber at the National Institute of Radiological Science (NIRS) by using the least-squares method. The line had high precision and stability, and the required detection time was less than that of ²¹⁴Po. An absorptive NVLS was used to collect radon and was found to be highly advantageous for α-spectrometry liquid scintillation measurements. Variations of the Ostwald coefficient due to changes in temperature and humidity, which affect radon absorption, were investigated and discussed. - Highlights: • This determination method for ²²²Rn in air was using a radon-²¹⁸Po calibration curve. • This curve was performed with measurements in a radon calibration chamber at the National Institute of Radiological Science. • The ability of this method was detectable atmospheric radon at its low natural concentration at the region of less than 500 Bq/m³. • A used non-volatile liquid scintillator for this measurement of radon combines as an absorbent for radon collector.